Pneumatic rock-drill



c. n. WELCH. PNEUMATIC ROCK DRILL APPLICATION FILED lFEB. I4, |920.

Patented Sept. 27, A1921.

UNITED STATES PATNT OFFCE.

CLARENCE R. WELCH, OF DENVER, COLORADO.

PNEUMATIC ROCK-DRILL.

Specification of Letters Patent.

Patented Sept. 27, 1921.

Application filed February 14, 1320. Serial No. 358,584.

use the same, reference being had to the ac` companying drawings, and tothe characters of reference marked thereon, which form a part of thisspecification.

The object of this invention is to provide a drill which is simple inconstruction and eiiicient in operation.

Briefly, the invention comprises a casing containing a pneumaticallyoperated hammer, and a doubleycam, one face of which is adapted toretract the hammer and the other 'ace to operate a reciprocable rodwhose forward end has a cam face controlling a block bearing a ratchetwhich rotates the drill.

In the drawings:

Figure 1 is a longitudinal section through the device, as indicated byline 1--1 of Fig. 2.

Fig. 2 is a cross section taken on the line 2-2 of Fig. 1, but showingthe mechanism rotated ninety degrees to the right from the position ofFig. 1.

The operating parts are housed in a casing 10 whose rear end plate 12 isprovided with a fitting 14 for supplying air under pressure. The hammer16 is journaled at both of its ends in the casing, and its rear end isprovided with an air chamber 18. Journaled upon the middle portion ofthe hammer 16 is a double-faced cam 20. One face 22 terminates at anabrupt wall 24, and this face 22 is adapted to engage a roller 26 on aprojecting tongue 28, which is guided by a longitudinally extending rod29. Opposite to the cam face 22 a bearing face 32 is provided, whichtravels upon rollers 30 mounted in the casing 10, and adapted to takethe thrust of said cam member 20. A gear 34 is fixed upon the cam member2O and is driven by a pinion 36 on a shaft 38 of an electric motor 40mounted upon the casing 10.

0n the side of the cam member 20, opposite from the cam face 22, asecond cam face 42 is provided. This is adapted to engage a projection44 on a reciprocating rod 46, which has at its forward end an offset 48,having an inclined or beveled cam face 50. The cam 42 of the member 20moves the rod 46 against the tension of a spring 51, which Aspring 51returns the rod 46 when freed by the cam 42. The cam face 50 of the rod46 engages a corresponding face of a block 52,

which is urged against said face 50 by means of a spring 54. The block52 is provided with a slot 56, in which there is mounted aspring-pressed dog 58, which is adapted to engage in teeth formed on aratchet 60,

drill steel 62.

In operation, the motor 40, through the medium of the gear 34, rotatesthe cam member- 20 upon the hammer 16, which is continually under airpressure in the chamber 18. When the cam face 22 frees the roller 26,the pressure propels the hammer 16 forwardly into engagement with theend of the drill. steel 62. As the cam memberA which rotates the chuckor holder for the casing and accommodated in a slot 66 in the hammer 16.

I claim:

1. In a rock drill, a casing, a hammer reciproeable therein, a drill tobe engaged by said hammer, a rotary cam, about the hammer, a gear on thecam to turn the same, means operated yby the cam to turn the drill, andpneumatic means to propel the hammer.

2. In a rock drill, a casing, a hammer reciprocable therein, a drillsteel to be engaged by said hammer, a' rotary cam, a reciprocable rodadapted to be engaged and operated by Said cam, a ratchetto turn saiddrill, a 'block having a dog to engage said ratchet, and a cam on saidreciprocable rod to move said block for the purpose of rotate ing saidratchet.

3. In a rock drill, a casing, a hammer reciprocable therein, a drill tobe engaged by said hammer, a rotary cam, a reciprocable rod direetlyengaged by said cam, a cam on said rod, and means operable by the lastmentioned cam to rotate said drill.

e. ln a rock drill, a easing, a hammer reciproeable therein, a hollowcam member positioned about said hammer, means to rotate said cammember, said cam member hav ing a face to retra'et the hammer, said camVhaving a second face, a. rod movable by said ,Second face, a drilladapted to be engaged by said hammer, and an operative connectionbetween said rod and said drill t0 rotate the drill.

5. ln a rock drill, a casing, a hammer reeipr-oeable therein, a @ammember journaled on the hammer, means to rotate Said Cam member, adrill, a reeiprocable rod, and a connection Ibetween said rod and saiddrill to rotate the drill, said cam member having a face to engage andretract said hammer and a second tace to engage and move 'said rod.

6.111 a rock drill, a easing, a hammer reoiproeable therein, a eammember journaled on the hammer, means to rotate said cam member, a.drill, a reeiproeable rod, and a connection between said rod and saiddrill to rotate the drill, said cam member having a face to engage andretract said hammer and a second Jface to engage and move said rod, saidhammer having` an air Chamber in the rear thereof for receiving airunder pressure to propelthe hammer.

In testimony whereof I atxV my'signature.

CLARENCE R. VELCH.

